The latest Android 4.2.2 Jelly Bean firmware comes with a plethora of intriguing features such as multi-user support, gesture typing, new quick settings option, lock-screen widget, new camera app, photo sphere, improved Google Now, new daydream feature and miracast display. As the custom firmware is still under development it may harbour a few untested bugs or broken features. However, all such issues are expected to be fixed in the upcoming updates.

NOTE: The instructions given in this guide are meant for reference purpose only. IBTimes UK will not be held responsible if the device is damaged during or after the ROM installation. Users are advised to proceed at their own risk.

Key Points to Note

SlimBean Build 2 ROM and the instructions given in this guide are applicable to the Galaxy S2 I9100G model only and will not work on any other device. Verify the device's model number by navigating to Settings > About Phone.

Back up important data and settings on the phone by using one of the recommended custom recovery tools such as ClockworkMod (CWM) or TWRP, as it creates a complete image of the existing phone setup.

Make sure that USB Debugging mode is enabled on the phone by navigating to Settings > Developer Options (if the device is running on Android 4.0 or later) or go to Settings > Applications > Development (if the phone is running on Android 2.3 or earlier). Otherwise, if the device is running Android 4.2, then perform the following steps:

Go to Settings > About Phone

Scroll down to the bottom of the screen and select Build Number

Tap the phone's Build Number seven times to unlock or reveal the hidden Developer Options under Settings. Then select the checkbox to enable USB Debugging mode under Settings > Developer Options.

Ensure that the phone has at least 80 percent battery charge.

Allow the newly installed ROM to stabilise for about five to ten minutes before starting to work on it.

Double check to see that the device is factory unlocked and rooted with ClockworkMod recovery (CWM) installed on it. Root Checker app may be downloaded and installed on the phone to verify if root access is working correctly, before proceeding with the custom ROM installation.

Connect the phone to computer with USB cable and mount the device's USB mass storage.

Without extracting, copy the downloaded ROM and Google Apps zip files to the root folder on the phone's SD card.

After the file transfer process is complete, disconnect the USB cable from computer and then Power off the phone.

Boot the phone into recovery mode. To do so, press and hold Volume Up, Home and Power button together and wait until the screen flashes. Then release all three buttons to enter CWM recovery. NOTE: Use Volume buttons to navigate between options and Power button to select an option in recovery.

Take a Nandroid Backup of the existing ROM, so that it can be restored later if the new ROM fails to work or if you want to return to the original ROM. To do a backup, choose Backup and Restore and hit Backup on next screen. Then return to main recovery menu once backup is done.

Perform a complete data wipe task to remove conflicts between the original and new ROM. To do so, first do Wipe Data/Factory Reset and then choose Yes on next screen to confirm. Wait for a few minutes until the data wipe process completes.

Return to CWM recovery main menu and click Wipe Cache Parition and once wipe process completes, choose Wipe Dalvik Cache under advance option. Once the wiping process completes, proceed to the next step.

Choose Install Zip from SD card and click Choose Zip from SD card. Then browse and locate the SlimBean Build 2 ROM zip file that was copied earlier in Step 3 and select it by tapping Power button. Confirm the ROM installation on next screen and the installation process will begin.

After the ROM installation is complete, repeat the previous step, but choose SlimBean Google Apps zip file instead of ROM zip to install the Google Apps package as well.

Once GApps is also installed, return to the main recovery menu and tap Reboot System Now. The phone will now automatically reboot into the new ROM. However, the first boot may be time-consuming (take about 5 minutes). So, please be patient.

Restoring Previous ROM: To return to the original ROM, boot into recovery, choose Backup and Restore and then restore the previous ROM by selecting it from the list.

Android 4.2.2 Jelly Bean based Slim Bean Build 2 custom ROM is now installed and running on the Galaxy S2 I9100G. Go to Settings -> About Phone to verify the firmware version installed.

Troubleshooting Steps

If the device is stuck or facing boot loop issues after flashing the ROM, then perform Wipe Cache Partition and Wipe Dalvik Cache about 4 to 5 more times before rebooting.

If the phone displays Status 7 error, then it means either the device being flashed is incompatible or a necessary kernel is missing on the device (for instance, if a Jelly Bean ROM is being upgraded then it is necessary to install a Jelly Bean kernel first).